<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>盒子模型</title>

    <style>
      div{
        border: 1px solid blue;
        width: 100px;
      }

      .div1{
        width: 100px;
        height: 100px;
        /*外边距*/
        /*margin: 50px;*/
      }

      .div2{
        width: 200px;
        height: 200px;
        /*内边距*/
        padding: 50px;
        /*
        设置盒子的属性，让 width 和 height 就是盒子最终的大小
         */
        box-sizing: border-box;
      }

      .div3{
        float: left;
      }

      .div4{
        float: left;
      }

      .div5{
        float: right;
      }
    </style>

</head>
<body>

    <div class="div2">
      <div class="div1"></div>
    </div>
    <div class="div3">aaaaa</div>
    <div class="div4">bbbbb</div>
    <div class="div5">ccccc</div>
</body>
</html>